Romney likely to boost lead Tuesday, but Obama looms

Mitt Romney is poised to pull further away from his rivals for the Republican presidential nomination in Tuesday\'s three primaries, but he faces a raft of challenges as he shifts his campaign toward US President Barack Obama. The party establishment is coalescing behind the former Massachusetts governor, with top Senate Republican Mitch McConnell saying Romney was all but certain to be the party\'s nominee to run against Obama in November. Wins on Tuesday in Wisconsin, Maryland and the US capital Washington would likely push Romney past the halfway mark in terms of the number of delegates he needs to clinch the nomination at the party convention in August. In the tightest race, in Wisconsin, where Romney and main rival Rick Santorum campaigned on Monday, Romney holds a 7.5 percentage point lead in polls, according to the RealClearPolitics website. He spent much of Monday chastising the Democratic incumbent and his \"government-centered society\" for failing to lead a recovery out of a deep recession and \"crushing\" the American dream. Romney also made it clear he was operating as the presumptive nominee. Obama would \"try to have people disqualify our nominee -- which will probably be me -- instead of talking about where we\'ve been and where we\'re going as a nation,\" Romney told a crowd in Green Bay, Wisconsin. While most signs point to Romney as the party\'s eventual flag-bearer, it gets cloudier looking beyond the pitched battle for the Republican nomination, with a new poll showing he has dug himself a deep hole against Obama. A USA Today/Gallup poll released Monday shows the Republican frontrunner slipping further behind Obama in a hypothetical one-on-one matchup.  The poll has Obama leading 49 to 45 percent over Romney nationally among registered voters, the largest lead to date in Gallup polling. Obama\'s lead in 12 swing states was even greater, with the president ahead 51-42 on average in key states like Florida, Ohio and Pennsylvania. That marks a dramatic shift in fortunes for Obama, who a month ago trailed Romney by two percentage points in swing states. The numbers also showed waning enthusiasm among Republican voters. \"The decline is especially apparent among Romney voters, whose enthusiasm has fallen 13 percentage points from January, and now is on par with Obama voters\' enthusiasm,\" Gallup researchers reported. Former Democratic president Bill Clinton, who prevailed in his own bruising nomination battle 20 years ago and went on to win the White House, said Romney had a tough task ahead. Clinton said he doubted Romney can turn around his fortunes in the general election. \"Mr Romney has a different challenge than I did,\" Clinton told ABC News. \"We never had to change what we were saying from primary to the general. The problem that governor Romney has, is his character attack was \'You don\'t really know what he believes. He did this, he says that.\'\" Romney has faced stubborn skepticism by the most conservative of voters, who fear that the candidate will moderate his views once he wins the nomination in order to appeal to independents. That scenario is fodder for Santorum, a former Pennsylvania senator who is a strong critic of abortion and gay rights who has tapped into conservative angst about the frontrunner, insisting Americans need a candidate \"whose policy is written on his heart.\" But McConnell said Romney \"is going to be an excellent candidate, and I think the chances are overwhelming that he will be our nominee.\" \"It is in the best interest of our party to get behind (Romney) and make the case against the president of the United States.\" Romney did just that in Milwaukee, telling a crowd that \"one of the reasons we\'re going to take over the White House is because (Obama) does not know how to make this economy work, and we do.\" \"What this president\'s doing -- regulation after regulation... new tax after new tax -- is slowly but surely crushing the dreams and the dreamers,\" he added. Romney has won 21 out of 34 contests so far and amassed some 565 delegates, and after Tuesday he will likely have more than half the 1,144 delegates needed for the nomination. Santorum, who has racked up 11 victories but has less than half Romney\'s delegate count, said he was determined to fight on despite efforts to anoint his rival. \"We\'re going to have a good result here in Wisconsin... maybe even sneak in and have an upset,\" he told Fox News on Monday.